Polymerizable compositions for manufacturing transparent polymeric substrates, resulting transparent polymeric substrates and their applications in the optical field

ABSTRACT

The compositions comprise:  
     (a) at least 40 parts by weight, preferably at least 50 parts by weight, of at least one thio(meth)acrylate monomer,  
     (b) at least one high Abbe number monomer,  
     (c) at the most 20 parts by weight, preferably at the most 15 parts by weight and more preferably 10 parts by weight of an aromatic polyvinyl monomer, and  
     (d) at least one polythiol, for 100 parts by weight of (a), (b), (c) and (d).  
     Application for the manufacture of optical lenses.

[0001] This invention relates to the field of polymerizable monomercompositions which, after polymerization, provide transparent polymericsubstrates, and their use for manufacturing optical lenses, moreparticularly ophthalmic lenses.

[0002] Polymerizable compositions have already been disclosed for themanufacture of ophthalmic lenses having a high refractive index.

[0003] Compositions comprising a polyoxyalkyleneglycol di(meth)acrylatemonomer, a monomer containing a bisphenol-A pattern and leading, throughhomopolymerization, to a polymer having a higher refractive index than1.55 and a urethane monomer having 2 to 6 (meth)acrylic end groups aredisclosed in EP-A-453, 149.

[0004] Polymerization is preferably a mixed UV/thermal one.

[0005] The patent application EP-745,621 discloses a photopolymerizablecomposition comprising:

[0006] a) 10 % to 70 % of a bis-2-[(meth)acryloylthioethyl] sulfide or amixture thereof with the bis [(meth)acryloylthiophenyl]sulfide,

[0007] b) 10 % to 60 % by weight of at least one poly(ethoxy)bisphenol-Adi(meth)acrylate type monomer,

[0008] c) 5 % to 30 % by weight of at least one aromatic or polycyclanicmono(meth)acrylate monomer,

[0009] d) 0 to 15 % by weight of a polyalkyleneglycol di(meth)acrylate,and

[0010] e) 0 to 10 % by weight of a polythiol.

[0011] Patent specification WO 96/38486 discloses polymerizablecompositions for the manufacture of optical lenses with a high index anda high Abbe number, comprising 20 % to 60 % by weight of an acrylate ormethacrylate monomer derived from a polycyclic olefin, more particularlya tricyclodecane acrylate or methacrylate derivative, 15 % to 60 % byweight of a di- or polythiol, 5 % to 50 % by weight of a divinyl orpolyvinyl monomer, and 0 to 20 % by weight of a polymerizable comonomerthat can be selected amongst methacrylates, acrylates,thiomethacrylates, thioacrylates, vinyls, vinylethers, allyls, epoxidesand the like.

[0012] The optical items produced from such compositions have highrefractive indices up to 1.6 or more and Abbe numbers of 38 or higher.

[0013] Although it is mentioned that the polymerizable compositionsdisclosed in this document can be polymerized thermally and/or by UVradiation, all the embodiments mention a thermal curing step, the timeperiod of which is particularly long (8 hours).

[0014] A polymerizable composition for the manufacture of ophthalmiclenses, which comprises 2.5 % to 100 % of a divinyl ester cyclicmonomer, 5 % to 30 % by weight of a di- or polythiol monomer and,optionally, 1 % 10 to 40 % by weight of a thiodiacrylate ordimethacrylate monomer, is described in patent specification WO97/44372.

[0015] As it is thus appreciated, numerous polymerizable compositionshave been offered in the prior art, leading to materials with arefractive index of 1.6 or higher, without being totally satisfactory ina view to obtaining transparent polymeric substrates, for use in theoptical field.

[0016] Thus, a first object of this invention aims at providing newpolymerizable monomer compositions leading to transparent polymericsubstrates.

[0017] In particular, the optical substrates must show the following setof features:

[0018] a high transparency (transmission being generally higher than 85%, and preferably, higher than or equal to 90 %/o), without or with avery little light diffusion,

[0019] a low density lower than 1.4, preferably lower than 1.3, and morepreferably lower than 1.2,

[0020] a refractive index in the range of 1.55 to 1.60,

[0021] a high Abbe number, in the range of 35 to 45, in order to avoidchromatic aberrations,

[0022] a lack of colour after polymerization, in particular a low yellowindex and a lack of yellowness in the course of time,

[0023] a good impact resistance (in particular, the uncoated glassshould preferably successfully satisfy the ball fall FDA test),

[0024] a good resistance to the action of static stresses,

[0025] a good abrasion resistance,

[0026] a good ability to several treatments (hard coating deposit,anti-reflection, adhesion and/or anti-shock primers,...), and inparticular a good colouration capacity,

[0027] a good ability to surfacing and projecting treatments, withoutthe glass global geometry being altered during these operations, and

[0028] a low water absorption rate.

[0029] A second object of this invention aims at providing compositionsthat could be easily and rapidly polymerized, in particular they couldbe polymerized with photopolymerization techniques or mixedphotopolymerization and thermal polymerization techniques allowing toreduce the cycle periods for the lens manufacture.

[0030] The polymerizable monomer composition according to the inventioncomprises:

[0031] (a) at least 40 parts by weight, preferably at least 50 and morepreferably 55 parts by weight of at least one thio(meth)acrylatemonomer,

[0032] (b) at least one high Abbe number monomer,

[0033] (c) at the most 20 parts by weight of an aromatic polyvinylmonomer, and

[0034] (d) at least one polythiol, for 100 parts by weight of (a), (b),(c) and (d).

[0035] The aromatic polyvinyl monomer typically represents 0.5 to 10parts by weight, preferably 1 to 5 parts by weight based on 100 parts byweight of (a), (b), (c) and (d).

[0036] Preferably, the high Abbe number monomer(s) represent(s) 10 to 40parts by weight, more preferably 10 to 30, and the polythiol 5 to 20parts by weight for 100 parts by weight of the mixture of monomers (a),(b), (c) and (d).

[0037] Preferably, the polythiol represents at the most 20 parts byweight and more preferably, at the most 15 parts for 100 parts by weightof (a), (b), (c) and (d).

[0038] Moreover, the polymerizable compositions may include for 100parts of the mixture of monomers (a), (b), (c) and (d), up to 30 partsby 35 weight of at least another copolymerizable monomer, different fromthe monomers of (a), (b), (c) and (d). Preferably, the otherpolymerizable comonomer represents no more than 20 parts by weight andmore preferably, no more than 10 parts by weight for 100 parts of themixture of monomers of (a), (b), (c) and (d). Preferably, such othercopolymerizable monomer is a radical copolymerizable monomer.

[0039] One of the advantages of the invention lies in that suchcompositions may be easily and rapidly photopolymerized.

[0040] The monomer or the mixture of monomers for the component (a) ofthe composition according to the invention encompasses any monomercomprising at least one thioacrylate or thiomethacrylate function.

[0041] In the present description and claims, it is understood by athio(meth)acrylate function a functional group of the formula:

[0042] wherein R₁, is H or -CH₃

[0043] Preferably, the monomers of the component (a) have the followingformula:

[0044] wherein:

[0045] R is a linear or branched, monovalent or polyvalent aliphatichydrocarbon radical, or a monovalent or polyvalent aromatic group,directly linked to the sulfur atom of the thio(meth)acrylate group(s)with an aromatic ring or by means of a linear alkl chain, said R radicalbeing able to include in its chain one or more groups selected amongst

[0046] R₁ is hydrogen or -CH₃, and

[0047] n is an integer from 1 to 6, preferably from 1 to 3.

[0048] The monovalent R radicals may include a linear or branched C₁-C₅alkyl group, the radicals of the formula:

[0049] wherein:

[0050] R₂ and R₃ are, independently from one another, H or a linear orbranched C₁-C₅ alkyl radical,

[0051] R₄ is a linear or branched C₁-C₅ alkyl radical, a C₇-C₁₀aralkylradical or a C₆-C₁₂ aryl radical, optionally substituted, in particularwith alkyl and/or halogen groups, and

[0052] m is an integer from 1 to 4.

[0053] The preferred monovalent R radicals may include: C₂H₅SCH₂CH₂-

[0054] Monomers of formula (I) in which n=1 and such as definedhereabove, are disclosed, amongst others, in U.S.-A-4,606,864,JP-63,316,766 and EP-A-0,384,725.

[0055] The divalent R radicals which fall within the scope of themonomers of formula (I) may include the linear or branched C₂-C ₁₀alkylene radicals that can include in their chain one or more

[0056] groups, the alkylidene radicals of the formula:

[0057] wherein R₇ and R6 are C₁-C₅ alkl radicals, the radicals of theformula:

[0058] wherein R₇ and R₈ are linear or branched C₁-C₅ aikylene groups,that can include one or more

[0059] groups in their chains and X is selected from the C₁-C₅ alkylradicals and halogens, and p is an integer from 0 to4, and the radicalsof the formula

[0060] wherein R₉ and R₁₀ are linear or branched C₁-C₅ alkyl radicals,that can include in their chains one or more

[0061] groups and r and s are 0 or 1.

[0062] Preferred divalent R radicals may include the radicals:

[0063] (CH₂₎ _(x) where x is an integer from 2 to 8,

[0064] (CH₂CH₂O)_(y)CH₂CH₂- radicals where y is an integer from 1 to 4,

[0065] (CH₂CH₂S)_(z)CH₂CH₂-radicals where z is an integer from 1 to 4,

[0066] (CH₂)_(u),(S(CH₂)_(v),)_(X),S-(CH₂)_(w), radicals where x′ is 0or 1 and u′, v′, w′ are integers from 2 to 6,

[0067] the radicals of the formula:

[0068] wherein u and v are integers from 1 to 4,

[0069] The particularly preferred divalent R radicals are:

[0070] Divalent monomers of the formula (I) are disclosed, inter alia,in EP-A-273,661, EP-A-273,710, EP-A-384,725.

[0071] The trivalent R radicals of the monomers of the formula (I) mayinclude C₃-C₁₀ alkyltriyl radicals that can include in their chains oneor more

[0072] the trivalent alkylaryl radicals the alkyl chains of which caninclude one or more -S- or -0- groups, and the trivalent aryl groups.

[0073] The trivalent R radicals or higher valency radicals may include:

[0074] etc.

[0075] The monomers of formula (l) being recommended in the presentinvention may include:

[0076] bis[(meti)acryloylthiophenyl]sulfide, where R, is a hydrogen atomor a methyl group.

[0077] The thio(meth)acrylate monomer(s) are preferably selected amongstnon aromatic thio(meth)acrylate monomers.

[0078] A preferred class of thio(meth)acrylate monomers includes themonomers of the formula:

[0079] wherein Y is a linear or branched C₂-C₁₂ alkylene group, a C₃-C₁₂cycloalkylene group, a C₆-C₁₄ arylene group or a C₇-C₂₆ alkarylenegroup, where the Y carbon chains can be interrupted by one or moreoxygen and/or sulfur atoms and R₁ is hydrogen or a methyl group,

[0080] the monomers of the formula:

[0081] wherein R, and Y are defined as above, and n is an integer from Ito 10, preferably 1 to 6, and the mixtures thereof.

[0082] A particularly preferred monomer of the formula (II) has thefollowing formula:

[0083] A particularly preferred monomer of the formula (III) has thefollowing formula:

[0084] In a preferred embodiment of the invention, the component (a)includes a mixture of monomers of formulae (IV) and (V) and optionally amonofunctional monomer of the formula:

[0085] In the preferred mixture, the monomer of formula (IV) represents10 % to 50 % by weight, the monomer of formula (V) 30% to 60% by weightand the monomer of formula (VI) 0 to 20 % by weight based on the mixturetotal weight.

[0086] The monomers of formulae (II) and (III) are disclosed in U.S.patent 5,384,379.

[0087] The second essential component of the polymerizable monomercompositions according to the invention comprises at least one high Abbenumber monomer.

[0088] By “high Abbe number monomer”, it is understood a monomer able togenerate, through homopolymerization, a transparent polymer with a highAbbe number, i.e. of at least 45, and preferably at least 50.

[0089] The high Abbe number monomer preferably comprises at least a nonaromatic hydrocarbon cyclic or polycyclic radical.

[0090] The high Abbe number monomer is preferably selected amongst atleast one of the monomers of the following formulae:

[0091] Where:

[0092] Y is a divalent radical selected from —O—, —CH₂—, —C(CH₃)₂—,—C(Hl)(CH₃)—,

[0093] Z is a divalent radical selected amongst —(CH₂)—O—, p being aninteger from 1 to 4 and

[0094] R_(a), R_(b) H or CH₃,

[0095] R_(e), R_(d) are, independently from one another, a linear orbranched alkyl radical with 1 to 6 carbon atoms,

[0096] R_(i), R_(j) are, independently from one another, a linear orbranched alkyl radical with 1 to 10 carbon atoms,

[0097] w″ is an integer from 1 to 3,

[0098] X″ is an integer from 0 to 3,

[0099] y″ is an integer from 0 to 3,

[0100] providing x″−y″≧ 1,

[0101] k″ is an integer from 0 to 6,

[0102] l″ is an integer from 0 to 6,

[0103] r″ is an integer from 0 to 6,

[0104] s″ is an integer from 0 to 6,

[0105] z″ is an integer from 0 to 3, and

[0106] t″ is an integer from 0 to 3.

[0107] The particularly preferred high Abbe number monomers are selectedamongst the monomers of the formulae:

[0108] Generally speaking, the preferred high Abbe number monomers aredifunctional di(meth)acrylate monomers.

[0109] The component (c) is an aromatic polyvinyl monomer or a mixtureof aromatic polyvinyl monomers.

[0110] In the present invention, the term “vinyl” is used in the strictsense and does not encompass functions of the acrylic or methacrylictype.

[0111] The aromatic polyvinyl monomer may be a monomer of the formula:[(CH₂=CH) (A)_(a)′] _(b)′ B

[0112] where B is selected amongst:

[0113] A is a divalent chain selected amongst:

[0114] Y′ is a hydrogen atom or an halogen,

[0115] a′=0, 1 or2,

[0116] b′ is an integer from 2 to 6, and

[0117] c′ is an integer from 1 to 4.

[0118] The preferred aromatic polyvinyl monomers are divinylbenzene,divinylnaphthalene and the derivates thereof, more particularlydivinylbenzene.

[0119] The polythiol monomers of component (d) of the compositionsaccording to the invention are well known in the art and can berepresented with the formula R′(SH)_(n′, wherein n′ is an integer of) 2or more, preferably from 2 to 5, and R′ is an aliphatic, aromatic orheterocyclic radical.

[0120] The polythiol compound is preferably a dithiol, trithiol ortetrathiol compound, more particularly a high Abbe number polythiol.

[0121] These polythiol compounds are well known in the art and aredisclosed, among others, in EP 394,495.

[0122] The dithiols useful in the present invention may include9,10-anthracenedimethanethiol, 1,11 -undecanedithiol,4-ethyl-benzene-1,3-dithiol, 1,2-ethanedithiol, 1,8-octanedithiol,1,18-octadecanedithiol, 2,5-dichlorobenzene-1,3-dithiol,1,3-(4-chlorophenyl)propane-2,2-dithiol, 1,1-cyclohexanedithiol,1,2-cyclohexanedithiol, 1,4-cyclohexanedithiol, 1,1-cycloheptanedithiol,1,1 -cyclopentanedithiol, 4,8-dithioundecane-1,11-2 0 -dithiol,dithiopentaecythritol, dithiothreitol, 1,3-diphenylpropane-2,2-dithiol,1,3-dihydroxy-2-propyl-2′,3′-dimercaptopropylether,2,3-dihydroxypropyl-2′,3′-dimercaptopropylether,2,6-dimethyloctane-2,6-dithiol, 2,6-dimethyloctane-3,7-dithiol,2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbenzene- 1,3-dithiol, 3,3-dimethylbutane-2,2-dithiol, 2,2- dimethylpropane-1,3-dithiol,1,3-di(4-methoxy-phenyl)propane-2,2-dithiol,3,4-dimethoxybutane-1,2-dithiol, 10,11 -dimercaptoundecanoic acid,6,8-dimercapto-octanoic acid, 2,5-dimercapto-1,3,4-thiadiazole,2,2′-dimercapto-biphenyl, 4,4′-dimercaptobiphenyl,4,4′-dimercaptobibenzyl, 3 ,4-dimercaptobutanol, 3,4-dimercaptobutylacetate, 2,3 -dimercapto- 1- propanol,1,2-dimercapto-1,3-butanediol, 2,3-dimercaptopropionic acid,1,2-dimercaptopropylnethylether,2,3-dimercaptopropyl-2′,3′-dimethoxypropylether, 3,4-thiophenedithiol,1,1 0-decanedithiol, 1,12-dodecanedithiol,3,5,5-trimethyl-hexane-1,1-dithiol, 2,5-toluenedithiol,3,4-toluenedithiol, 1,4-naphthalenedithiol, 1 ,5-naphthalenedithiol,2,6- naphthalenedithiol, 1,9-nonanedithiol, norbomene-2,3-dithiol,bis(2-mercaptoisopropyl)ether, bis(11-mercaptoundecyl)sulfide,bis(2-mercaptoethyl)ether, bis(2-mercaptoethyl)sulfide, bis(18-mercatooctadecyl)sulfide, bis(8-mercaptooctyl)sulfide,bis(12-mercaptodecyl)sulfide, bis(9-mercaptononyl)sulfide,bis(4-mercaptobutyl)sulfide, bis(3-mercaptopropyl)ether,bis(3-mercaptopropyl)sulfide, bis(6-mercaptohexyl)sulfide,bis(7-mercaptoheptyl)sulfide, bis(5-mercaptopentyl)sulfide,2,2′-bis(mercaptomethyl)acetic acid, 1,1-bis(mercaptomethyl)cyclohexane,bis(mercaptomethyl)durene, phenylmethane-1,1-dithiol,1,2-butane-dithiol, 1,4-butanedithiol, 2,3-butanedithiol,2,2-butanedithiol, 1,2-propanedithiol, 1,3-propanedithiol,2,2-propanedithiol, 1,2-hexanedithiol, 1,6-hexanedithiol,2,5-hexanedithiol, 1,7-heptanedithiol, 2,6-heptanedithiol,1,5-pentanedithiol, 2,4-pentanedithiol, 3,3-pentanedithiol,7,8-heptadecanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol,1,4-benzenedithiol, 2-methylcyclohexane-1,1-dithiol,2-methylbutane-2,3-dithiol, ethyleneglycol dithioglycolate, ethyleneglycol bis(3-mercaptopropionate). The trithiols may include1,2,3-propanetrithiol, 1,2,4-butanetrithiol, trimethylolpropanetrithiolglycolate, trimethylolpropane tris(3-mercaptopropionate),pentaerythritol trithioglycolate, pentaerythritoltris(3-mercaptopropionate), 1,3,5-benzenetrithiol and2,4,6-mesitylenetrithiol.

[0123] The polythiols useful in the compositions of the presentinvention may further include neopentane tetrathiol,2,2′-bis-(mercaptomethyl)-1,3-propanedithiol, pentaerythlritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis (thioglycolate),1,3,5-benzenetrithiol, 2,4,6-toluenetrithiol, 2,4,6-methylenetrithioland the polythiols of the following formulae:

[0124] (HS CH₂CH₂ COO CH₂)₃ C C₂H₅ (TTMP), and4-mercaptomethyl-3,6-dithia-1,8-octanedithiol.

[0125] The preferred polythiols according to the present invention areethyleneglycol bis(thioglycolate), trimethylolpropanetris(3-mercaptopropionate), pentaerythritol tetrakis thiopropionate(PETP), 4- mercaptomethyl-3,6-dithia-1,8-octanedithiol (MDO),bis(2-mercaptoethyl)sulfide (DMDS) and pentaerythritol tetrakisthioglycolate (PETG).

[0126] As previously indicated, besides the monomers of components (a),(b), (c) and (d), the compositions according to the invention mayinclude other copolymerizable monomers, particularly radicalcopolymerizable monomers.

[0127] Such monomers make it possible to match the properties of theresulting transparent substrates.

[0128] These monomers may be present in the compositions of theinvention in a proportion of 0 to 30% based on the total weight of themonomers of components (a), (b), (c) and (d), preferably 0 to 20% andmore preferably 0 to 10%.

[0129] Such monomers may include:

[0130] alkyl(meth)acrylates such as methyl(meth)acrylate andethyl(meth)acrylate, cycloalkyl (meth)acrylates such as cyclohexyl(meth)acrylate and dicyclopentyl (meth)acrylate, phenyl (meth)acrylate,benzyl (meth)acrylate, naphthyl (meth)acrylates, phenoxyalkyl(meth)acrylates such as phenoxyethyl (meth)acrylate and phenoxybutyl(meth)acrylate, alkyleneglycol di(meth)acrylates such as ethyleneglycoldi(meth)acrylate and propyleneglycol di(meth)acrylate,polyalkyleneglycol di(meth)acrylates such as polyethyleneglycoldi(meth)acrylates and polybutyleneglycol di(meth)acrylates,neopentylglycol di(meth)acrylate and the derivates of bisphenol-Adi(meth)acrylates, poly(meth)acrylate urethanes.

[0131] The bisphenol-A di(meth)acrylates compounds may include thecompounds of the formula:

[0132] wherein R₅ is H or CH₃ and n₁−n₂ has a mean value in the range of0 to 40.

[0133] Preferred compounds having the above-mentioned formula are thosefor which R₅=CH₃ and n₅−n₂ =2,6 (EBADMA), n₁+n₂=4 (DBADMA), n_(1−n) ₂=10 (OBADMA) and n_(1−n) ₂=30.

[0134] The polymerizable compositions according to the invention mayalso include conventionally used additives in polymerizable compositionsfor moulding optical items, more particularly spectacle glasses, in theconventional proportions, namely inhibitors, dyes, UV absorbers,perfumes, deodorants, antioxidants and anti-yellowing additives.

[0135] More particularly, the anti-yellowing agents such as thosedisclosed in the U.S. patents n° 5,442,022, 5,545,828, 5,702,825 and5,741,831 may be used.

[0136] The preferred anti-yellowing agent is 3-methyl 2-butene l-ol(MBOL).

[0137] Triphenylphosphine (TPP) and Irganox® 1010(pentaerthitol-tetrakis[3(3,5-di-tert.-butyl-4-hydroxyphenyl)propionate](CG 1010) may be mentioned as preferred examples of antioxidant agents.

[0138] Perfumes make it possible to hide the smell from thecompositions, more particularly in surfacing operations.

[0139] The compositions according to the invention generally includepolymerization initiators, preferably photoinitiators or mixtures ofphotoinitiators and thermal initiators, in a proportion of 0.001% to 5%by weight based on the total weight of the polymerizable monomerspresent in the composition.

[0140] The photoinitiators useful in the polymerizablecompositions-according to the invention may include more particularly2,4,6-trimethylbenzoyldiphenyl-phosphine oxide (TPO),1-hydroxycyclo-hexylphenylketone, 2,2-dimethoxy- 1 ,2-diphenylethane1-one, alkylbenzoylethers, the commercially available photoinitiatorfrom Ciba-Geigy Corporation under the tradename CGI 1700, which is a25/75 mixture of a compound of the formula:

[0141] and a compound of the formula:

[0142] and the CGI 1850 photoinitiator commercially available from CibaGeigy Corporation, which is a 50/50 mixture (by weight) of compound Aand Irgacure® 184 of the formula:

[0143] Another preferred photoinitiator is CGI 819 from Ciba GeigyCorporation of the formula:

[0144] Other photoinitiators of the same type may also be used, such asthat of the formula:

[0145] As previously mentioned, the preferred polymnerizablecompositions according to the invention are photopolymerizablecompositions comprising one or more photoinitiators.

[0146] Still preferably, the polymerizable compositions according to theinvention are photo- and thermopolymerizable compositions including botha polymerization photoinitiator and a polymerization thermal initiator.

[0147] The thermal polymerization initiators are compounds which arewell known in the art and may include peroxides, such as benzoylperoxide, cyclohexyl peroxydicarbonate, isopropyl peroxydicarbonate andtert-butylperoxy(2-ethyl hexanoate).

[0148] The present invention will now be described more in details inthe following examples. In such examples, unless otherwise mentioned,all the percentages and parts are expressed in weight.

Examples 1 to 6

[0149] 1) Preparation of the polymerizable compositions

[0150] Six compositions of polymerizable monomers according to theinvention have been formulated by mixing the monomers indicated in tableI hereunder. TABLE I Comp. Comp. Comp. Comp. Comp. Comp. 1 2 3 4 5 6(Parts by weight) Thiométhacry- late PLEX ® 6856 58.2 58.1 56.9 52.258.2 57 High Abbe number monomer DCPA 22.2 22.2 20.9 22.3 22.2 21.8 DVB3.6 3.6 3.9 4.7 3.6 3.6 Polythiol monomer PETG 15.3 10.4 17.9 12.4 8.36.9 Other monomer DMDS — 5 — 7.7 7.0 10.0 Anti-yellowing agent MBOL 0.300.30 — 0.3 0.3 0.3 UV absorber UV 5411 0.1 0.1 0.1 0.1 0.1 0.1Photoinitiator CGI 819 0.3 0.3 0.3 0.3 0.3 0.3

[0151] 2) Casting process

[0152] The compositions prepared as above mentioned are cast into mouldsmade of two mineral glass mould parts, soda cleaned beforehand andassembled in parallel with a 2mm BARNIER adhesive strip. The cast iscarried out with the following steps of:

[0153] taking out the composition using a (20 ml) sterile syringe,

[0154] partial disassembling the adhesive strip for creating an opening,

[0155] inserting the syringe tip into the opening,

[0156] injecting the composition into the mould, and

[0157] repositioning the adhesive strip for sealing the mould.

[0158] 3) Photochemical prepolvmerization

[0159] The filled moulds are placed in a photochemical polymerizationoven provided with two U.V. PRIMA lamps (mercury lamps) positioned oneither side at equal distance from the moulds and each mould receives a12 mW/cm² illumination for 30 seconds.

[0160] Infrared measures make it possible to follow the conversion ofthe double (meth)acrylic bonds depending on the UV irradiation time.

[0161] 4) Photochemical polymerization

[0162] The assembly is then placed in a UV (mercury lamp) oven and issubjected to an increasing illumination up to a value of 200 mW/cm², fora two minute period. The glass pieces are then released and checkedusing an arc lamp. A final annealing allows to complete thepolymerization and to release the residual stresses of the resultingsubstrate.

[0163] The features of the resulting substrates are indicated in tableII.

[0164] The YI yellowing index has been measured using the ASTM D 1925standard for 2 mm thick glasses.

[0165] Tg measurement is done using DMA (dynamic mechanical analysis) ona planar 5.2 ×1×2 cm (thickness) sample.

[0166] The test is performed in a 3 point bending.

[0167] Tg corresponds to the ratio maximum.

[0168] E″ (loss modulus)/E′(conservation modulus) The refractive indicesn_(e) (λ=546 nm) and the Abbe numbers γ_(e have been determined at) 25°C. with a Bellingham-Stanley Limited Abbe 60/TR refractometer usingseveral lamps (sodium, mercury and cadmium) as light sources.

[0169] The DMA analyses have been carried out with a Rheometrics SolidAnalyzer RSA II apparatus on 52×10×2 mm samples, at a 1 Hz frequency andin a temperature range of −50° C. to 170° C. at 2° C./minute.

[0170] The results are given in table II. TABLE II Comp. 1 Comp. 2 Comp.3 Comp. 4 Comp. 5 Comp. 6 n_(e) 1.587 1.592 1.587 1.591 1.593 1.596γ_(e) 40 40 40.5 41 40 40 d 1.27 1.27 1.28 1.27 1.27 1.27 YI 1.2 1.2 1.91.5 1.7 1.6 E′ 25° C. (Mpa) 3500 3260 3500 3300 — 3200 E′ 100° C. (Mpa)860 450 635 185 — 190 Tg (° C.) 104 96 102 92 — 88

[0171] A resistance test to a mechanical stress of a quasi static typeis performed according to the NF EN ISO 14889 standard on 12 glasspieces corresponding to composition no. 6 in table I hereabove andhaving a central average thickness of 1.22 mm.

[0172] All the glass pieces being tested satisfie the corresponding testsuccessfully (no starred glass, no material loss).

[0173] An impact resistance test (according to the ball fall FDAAmerican standard (16g, 1.27m)) is performed on a sample of 12 glasspieces corresponding to composition no. 6 in table I hereabove andhaving a central thickness of 1.23 +/−0.03 mm.

[0174] The 12 tested glass pieces satisfie the FDA test successfully (nobreak, no starring).

Examples 7 to 12

[0175] Six compositions of polymerizable monomers according to theinvention have been formulated from a mixture of monomer of formula (IV)and monomer of formula (VII) in respective amounts of 35 % and 65 % byweight (TMA from PPG).

[0176] where n′ is an integer from 1 to 10.

[0177] The compositions are indicated in Table III. TABLE III Comp.Comp. Comp. Comp. Comp. Comp. 7 8 9 10 11 12 Thiomethacry- 59.5 62.563.6 58.1 61 63 late TMA (PPG) High Abbe 21.8 21.9 21.9 22.2 22 20number mono- mer DCPA DVB 3 3 4 5.4  3  3 Polythiol mon- omer PETG 15 129.9 9.2 14 — DMDS — — — 4.5 —  4 Other monomer 10 OBADMA

[0178] All formulations contain:

[0179] 0.3 % MBOL (anti yellowing agent)

[0180] - 0.3 % CGI 819 (photoinitiator)

[0181] 0.1 % UV 5411 (UV absorber)

[0182] Casting, prepolymerisation, thermal polymerisation and annealingprocess, as well as the characterizations made are identical to thosedisclosed in connection with examples 1 to 6.

[0183] The results are given in Table IV. TABLE IV Comp. Comp. Comp.Comp. Comp. Comp. 7 8 9 10 11 12 n_(e) 1.593 1.594 1.595 1.596 1.5941.595 γ_(e) 40-41 39-40 39 40 40 39 d 1.29 1.29 1.28 1.27 1,29 1.26 YI(20/10) 1.55 1.6 2.1 1.6 1.5 1.7 E′ 25° C. 2960 3000 3000 2700 2200(Mpa) E′ 100° C. 110 170 360 110 120 — (Mpa) Tg (° C.) 79 83 100 82 84Impact Thickness Thickness (FDA) at center = at center = 1.26 mm 1.25 mm20 glasses/ 31 glasses/ 20 OK 31 OK

1. A polymerizable monomer composition, characterized in that itcomprises: (a) at least 40 parts by weight, preferably at least 50 partsby weight, of at least one thio(meth)acrylate monomer, (b) at least onehigh Abbe number monomer, (c) at the most 20 parts by weight, preferablyat the most 15 parts by weight more preferably at the most 10 parts byweight, of an aromatic polyvinyl monomer, and (d) at least onepolythiol, for 100 parts by weight of (a), (b), (c) and (d).
 2. Acomposition according to claim 1, characterized in that it comprises 10to 40 parts by weight of the high Abbe number monomer(s).
 3. Acomposition according to claim 1 or 2, characterized in that itcomprises 5 to 20 parts by weight of the polythiol(s).
 4. A compositionaccording to any one of claims 1 to 3, characterized in that it includes0.5 to 10 parts by weight, preferably I to 5 parts by weight of thearomatic vinyl monomer for 100 parts by weight of (a), (b), (c) and (d).5. A composition according to any one of claims 1 to 4, characterized inthat it comprises moreover, for 100 parts by weight of monomers (a),(b), (c) and (d), up to 30 parts by weight of at least anothercopolymerizable monomer different from the monomers (a), (b), (c) and(d).
 6. A composition according to claim 5, characterized in that theother monomer(s) are radical copolymerizable monomer(s).
 7. Acomposition according to any one of the preceding claims, characterizedin that the thio(meth)acrylate monomer (a) is selected from thecompounds of the formula:

wherein R is a linear or branched, monovalent or polyvalent aliphatichydrocarbon radical, or a monovalent or polyvalent aromatic group,directly linked to the sulfur atom of the thio(meth)acrylate group(s)with an aromatic ring or by means of a linear alkyl chain, the R radicalcomprising optionally in its chain one or more groups selected amongst

R11 is hydrogen or -CH₃, and n is an integer from 1 to 6, preferablyfrom 1 to
 3. 8. A composition according to any one of the precedingclaims, characterized in that the thio(meth)acrylate monomer (a) is nonaromatic.
 9. A composition according to any one of the preceding claims,characterized in that the thio(meth)acrylate monomer(s) (a) are selectedamongst the monomers of the formula:

wherein Y is a linear or branched C₂-C₁₂ alkylene group, a C₃-C₁₂cycloalkylene group, a C₆-C₁₄ arylene group or a C₇-C₂₆ alkarylenegroup, the carbon chains of Y can be interrupted by one or more oxygenand/or sulfur atoms and R₁ is hydrogen or a methyl group, the monomersof the formula:

wherein R₁ and Y are defined as above, and n is an integer from 1 to 10,preferably 1 to 6, and the mixtures thereof.
 10. A composition accordingto claim 9, characterized in that the thio(meth)acrylate monomer is amixture of: 35 % by weight of a monomer of formula

65 % by weight of a monomer of formula

where n′is an integer from 1 to
 10. 11. A composition according to claim9, characterized in that the thio(meth)acrylate monomers of (a) comprisea mixture in percent by weight based on the total weight of the mixture,of: (1) 10 % to 50 % of a monomer of the formula:

(2) 30 % to 60 % of a monomer of the formula:

(3)0 to 20 % of a monomer of the formula:


12. A composition according to any one of the preceding claims,characterized in that the high Abbe number monomer(s) are selectedamongst the monomers of the formulae:

wherein Y is a divalent radical selected amongst —O—, —CH₂—, —C(CH₃)₂—,—C(H)(CH₃)—, Z is a divalent radical selected amongst —(CH₂)_(p)—O—, pbeing an integer from 1 to 4, and

R_(a, R) _(b) are H or CH₃, R_(C, R) _(d) are, independently from oneanother, a linear or branched alkyl radical with 1 to 6 carbon atoms,R_(I),R_(j are, independently from one another, a linear or branched alkyl radical with)1 to 10 carbon atoms, w″ is an integer from 1 to 3, x″ is an integerfrom 0 to 3, y″ is an integer from 0 to 3, providing x″+y″>1, k″ is aninteger from 0 to 6, I″ is an integer from 0 to 6, r″ is an integer from0 to 6, s″ is an integer from 0 to 6, z″ is an integer from 0 to 3, t″is an integer from 0 to
 3. 13. A composition according to claim 12,characterized in that the is high Abbe number monomers are selectedamongst monomers of the formulae:


14. A composition according to any one of the preceding claims,characterized in that the aromatic polyvinyl monomer(s) are selectedamongst the monomers of the formula: [(CH₂=CH) (A)_(a′)]_(b′)B where Bis selected amongst:

A is a divalent chain selected amongst:

Y′ is a hydrogen atom or an halogen a′ =0, 1 or 2, b′ is an integer from2 to 6, and c′ is an integer from 1 to
 4. 15. A composition according toclaim 14, characterized in that the aromatic polyvinyl monomer(s) is/areselected from divinylbenzene, divinylnaphthalene or their derivates. 16.A composition according to any one of the preceding claims,characterized in that the polythiol monomer(s) (c) are selected from themonomers of the formula R′(SH)_(n′), wherein R′ is an aliphatic,aromatic or heterocyclic radical and n′ is an integer of 2 or more,preferably 2 to
 5. 17. A composition according to claim 16,characterized in that the polythiol monomer (c) is selected amongstethyleneglycol bis(thioglycolate), trimethylolpropanetris(3-mercaptopropionate), pentaerythritol tetrakis thiopropionate(PETP), 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol (MDO),bis(2-mercaptoethyl)sulfide (DMDS) and pentaerytiritol tetrakisthioglycolate (PETG).
 18. A composition according to any one of thepreceding claims, characterized in that it comprises moreover aphotoinitiator and/or a thermal initiator.
 19. A composition accordingto any one of the preceding claims, characterized in that it isphotopolymerizable.
 20. A transparent polymerized organic substrateresulting from the polymerization of a composition, according to any oneof the preceding claims.
 21. A substrate according to claim 20,characterized in that it forms an optical or ophthalmic lens.